Mechanism and kinetics of diuron oxidation by hydroxyl radical addition reaction
| Autor: | Gunasekaran Manonmani, Kittusamy Senthilkumar, Lakshmanan Sandhiya |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Addition reaction
Atmosphere Hydroxyl Radical Health Toxicology and Mutagenesis Radical Photodissociation General Medicine Time-dependent density functional theory 010501 environmental sciences Photochemistry 01 natural sciences Pollution Adduct Kinetics chemistry.chemical_compound Reaction rate constant chemistry Diuron Environmental Chemistry Hydroxyl radical Density functional theory Oxidation-Reduction 0105 earth and related environmental sciences |
| Zdroj: | Environmental Science and Pollution Research. 27:12080-12095 |
| ISSN: | 1614-7499 0944-1344 |
| DOI: | 10.1007/s11356-020-07806-4 |
| Popis: | Diuron is a phenyl urea herbicide used to control weeds in agricultural lands. The degradation of diuron in the atmosphere takes place dominantly via reaction with OH radicals. In this work, the OH addition reaction of diuron has been studied by using density functional theory methods M06-2X, ωB97X-D and MPWB1K with 6-31G(d,p) basis set. The calculated thermochemical parameters show that OH addition reaction occurs favourably at C2 position of diuron. The rate constant is calculated for the favourable initial reaction pathway by using canonical variational transition state theory with small curvature tunnelling (SCT) correction over the temperature range of 200–1000 K. The reaction of initially formed diuron-OH adduct intermediate with O2 leads to the formation of peroxy radical intermediate. The reaction of peroxy radical intermediate with HO2 and NOx (x = 1, 2) radicals is studied in detail. The results obtained from time-dependent density functional theory (TDDFT) calculations show that the intermediates and products formed from oxidation of diuron can be easily photolyzed in the sunlight. This study provides thermodynamical and kinetic data for the atmospheric oxidation of diuron by OH radical addition reaction and demonstrates the atmospheric chemistry of diuron and its derivatives. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink